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Merge pull request #25630 from taosdata/54liuyao-patch-17 

Update 12-distinguished.md
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@ -31,7 +31,7 @@ A PARTITION BY clause is processed as follows:
select _wstart, location, max(current) from meters partition by location interval(10m)
```
The most common usage of PARTITION BY is partitioning the data in subtables by tags then perform computation when querying data in a supertable. More specifically, `PARTITION BY TBNAME` partitions the data of each subtable into a single timeline, and this method facilitates the statistical analysis in many use cases of processing timeseries data. For example, calculate the average voltage of each meter every 10 minutes£º
The most common usage of PARTITION BY is partitioning the data in subtables by tags then perform computation when querying data in a supertable. More specifically, `PARTITION BY TBNAME` partitions the data of each subtable into a single timeline, and this method facilitates the statistical analysis in many use cases of processing timeseries data. For example, calculate the average voltage of each meter every 10 minutes£º
```sql
select _wstart, tbname, avg(voltage) from meters partition by tbname interval(10m)
```
@ -44,12 +44,12 @@ Aggregation by time window is supported in TDengine. For example, in the case wh
window_clause: {
SESSION(ts_col, tol_val)
| STATE_WINDOW(col)
| INTERVAL(interval_val [, offset]) [SLIDING (sliding_value)] [FILL({NONE | VALUE | PREV | NULL | LINEAR | NEXT})]
| INTERVAL(interval_val [, interval_offset]) [SLIDING (sliding_value)] [FILL({NONE | VALUE | PREV | NULL | LINEAR | NEXT})]
| EVENT_WINDOW START WITH start_trigger_condition END WITH end_trigger_condition
}
```
Both interval_val and sliding_value are time durations which have 3 forms of representation.
Both interval_val and sliding_value are time durations, and interval_offset is the window offset, interval_offset must be less than interval_val, There are 3 forms of representation.
- INTERVAL(1s, 500a) SLIDING(1s), the unit char should be any one of a (millisecond), b (nanosecond), d (day), h (hour), m (minute), n (month), s (second), u (microsecond), w (week), y (year).
- INTERVAL(1000, 500) SLIDING(1000), the unit will the same as the queried database, if there are more than one databases, higher precision will be used.
- INTERVAL('1s', '500a') SLIDING('1s'), unit must be specified, no spaces allowed.